This invention broadly relates to a manufacturing system and manufacturing method for adjusting the performance of manufacturing operations or steps in manufacturing components having three-dimensional external structural characteristics by using accumulated component data.
In a gas turbine (e.g., jet) engine, air is drawn into the front of the engine, compressed by a shaft-mounted compressor, and mixed with fuel. The mixture is burned, and the hot exhaust gases are passed through a turbine mounted on the same shaft. The flow of combustion gas turns the turbine by impingement against an airfoil portion of the turbine blades and vanes, which turns the shaft and provides power to the compressor.
Turbine blades used in compressors, turbines, vanes, blisks, etc., comprise an airfoil. These turbine airfoils typically have relatively complex configurations and shapes with three-dimensional external and internal structural characteristics that contribute to this complexity. For example, in addition to the typically curved or twisted external shape of turbine airfoils, many turbine airfoils have one or more internal cooling passages with openings or holes at the external surface(s) of the airfoil for the passage of cooling air out to remove heat from the interior of the airfoil and, in some cases, to provide a boundary layer of cooler air at the external surface of the airfoil. To attain maximum cooling efficiency, these internal cooling passages are frequently positioned as close to the external surface of the airfoil as is consistent with maintaining the required mechanical properties of the airfoil, e.g., as little as about 0.020 inches (508 microns) in some cases. For non-blisk structures, turbine blades, typically further comprise a root portion extending from the airfoil having a dovetail formed therein so that the turbine blade can be removably received by a corresponding slots positioned along the periphery of the hub, disk, shaft, etc., of the compressor, turbine, vane, etc.
Many turbine blades are typically required for the hub, disk, shaft, etc., of each compressor, turbine, vane, etc., present in the gas turbine engine. This can make the consistent and reproducible manufacture of a plurality, and especially a multiplicity, of such components having such complex three-dimensional external and internal structural characteristics extremely difficult to achieve. The current manufacture of a complex component such as a turbine blade typically involves starting with a cast metal form having some but not all external and internal structural characteristics, such as the general airfoil shape or configuration, the internal cooling passages within the airfoil, etc. This cast form is then processed in several different manufacturing operations or steps (e.g., cutting, drilling, milling, welding, coating, etc.) that are carried out in sequence, for example, to form the dovetail, to form the openings or holes in the surface of the blade to connect to the internal cooling passages, to apply a protective coating to the external and/or internal surfaces of the blade, etc. The result of such manufacturing operations/steps is a finished or final turbine blade that hopefully resembles and is sufficiently close to a previously established set of specifications or requirements for the blade.
Current manufacturing systems for obtaining finished or final components such as turbine blades typically have various levels of numerical control. For example, the tool paths used for a given manufacturing operation or step can be electronically generated from master models previously established and determined for that component. This hopefully insures that each manufacturing operation or manufacturing step (e.g., grinding the cast form to form a dovetail, drilling openings or holes through the external surface of the airfoil to connect to the internal cooling passages, applying a protective coating to the external and/or internal surfaces of the airfoil, etc.), achieves the desired result, provided that the original cast form meets or is close to previously established specifications or requirements at the start, and also provided that each manufacturing operation or step is carried out according to the previously established specifications or requirements as the cast form is processed through the manufacturing system. In other words, the assumption is that the processed turbine blade, before and after each manufacturing operation or step in the manufacturing system, meets or satisfies some target condition, or more typically a set of target conditions from the product specifications or requirements. Unfortunately, in practice, the “perfect” or “ideal” typically does not occur in standard manufacturing systems/methods, especially with mass produced components such as turbine blades.
Instead, before and after each manufacturing operation or step of the manufacturing system/method, it is likely that there will be at least some deviation or variation in the processed blade from the previously determined and desired product specifications or requirements. These deviations and variations occur because of the complex external and/or internal structural characteristics of the turbine blade, and in particular the airfoil. These deviations and variations can also be present in the initial cast form of the turbine blade that is supplied to the manufacturing system/method. These deviations and variations tend to be carried forward to each subsequent manufacturing operation or step, and thus accumulate in the processed blade as it advances through the manufacturing system/method. While any deviation or variation in the processed blade can adversely affect the performance of each subsequent operation or step, it is usually the collection or accumulation of such deviations and variations as the processed blade moves through the manufacturing system/method that causes the resulting processed turbine blade to stray significantly from the previously determined product specifications or requirements for final turbine blade. Indeed, the resulting processed turbine blade can stray so much from these product specifications or requirements as to be unusable and therefore scrapped or discarded.
At the various operations or steps of a manufacturing system/method, a processed component such as a turbine blade is typically inspected, measured, examined, probed or otherwise analyzed to determine whether the processed component meets the previously established specifications or requirements for that particular operation or step. These inspections or other analyses can range from visual (human) inspections, including the use of manual devices such micrometers, caliper gauging, etc., to more sophisticated analytical equipment and/or methods such as x-ray, airflow, pressurization, ultrasonic, eddy current inspections, etc. Such analyses can also be electronically controlled and can lead to the generation of precise data on the processed component at a given manufacturing operation or step of the manufacturing system/method. Unfortunately, this data is currently used only to assess overall trends in the manufacturing system associated with the given inspection or other analysis, and to make changes to the manufacturing system/method to correct long term trends outside the acceptable, defined limits.
Accordingly, it would be desirable to provide a manufacturing system and method for manufacturing components having three-dimensional external structural characteristics, as well as three-dimensional internal structural characteristics, for example, turbine components comprising airfoils having internal cooling passages, that has the ability to: (1) adjust the performance of one or more manufacturing operations/steps as the component is processed through the manufacturing system/method, even if there are deviations or variations in the characteristics of the starting component form and/or in how each manufacturing operation/step is carried out; (2) obtain a resulting finished or final component that achieves or more closely achieves previously determined product specifications or requirements; and/or (3) use the collected and accumulated analytical data (or relevant portion thereof) as an aid in carrying the various manufacturing operations or steps.